1. Technical Field of the Invention
This invention is directed to an extract of a plant and use thereof, particularly to an isolated protein from a traditional Chinese herbal medicine (TCM), Yuzhu, Polygonatum odoratum (Liliaceae) and use thereof.
2. Description of the Related Art
Yuzhu, Polygonatum odoratum (Mill) Druce, belonging to liliaceae, is a famous Chinese herbal medicine, and commonly found in dry to moist shaded areas where the soil is rich. This perennial stands one to three feet high at maturity, producing small, white, and bell-shaped flowers and dark purple fruits that hang from the leaf axils largely in pairs. The rhizome itself is edible, and has traditionally been used for treatment of coughing, fever and weakness due to malaise, and for treatment of hyperlipidemia, preventing cardiovascular disease and improvement of cardiac muscle due to the toxicity of digitalis, as well as treating paralysis due to stroke. Hence, it is widely cultivated in temperate regions of China, from Northern Guandong to Northern-east China provinces.
In the PRC Pharmacopoeia (2000), Polygonatum odoratum is an official plant species for Yuzhu (Rhizoma Polygonati Odorati). However, other related species have been also used as “Yuzhu” in the market. The criterion of quality control for Yuzhu, according to the PRC Pharmacopoeia, is the polysaccharide content in it. The content of polysaccharide is based on the glucose content (not less than 6% of its dry-weight) by sulfuric-phenol methods. However, the PRC Pharmacopoeia provides no data on the function of proteins.
In China, the firstly recorded use of Yuzhu might go back to the “Shen'nong Bencaojing” of the first century AD. It is considered a yin tonic, and is thought to be particularly applicable to problems affecting the digestive, respiratory and cardiovascular systems. Taking advantage of the long history of consumption by the Chinese to treat various diseases in the complex decoctions without any obvious adverse effect, the protein from this herb, therefore, can be considered relatively safe for human consumption.